In an image information processing technique wherein an original document containing letters or pictures is converted into sequential electrical signals by way of a photoelectric conversion means and, after being processed, is outputted as electrical signals or visible images, it is sometimes necessary to transcribe a certain portion of the original document at another place.
In this case, it is considered that an operator may designate the coordinate position on the original document and the coordinate position on the output images of the portion to be transcribed. However, since this method is troublesome, it is preferred to prepare an original document in which desired rectangular frames are previously described, to read the position, size and the like of the rectangular patterns automatically, recognize them, and then transcribe them automatically.
This invention concerns an apparatus for recognizing rectangular patterns or an original document and specifically, this invention concerns a rectangular pattern recognition apparatus capable of recognizing at least one rectangular pattern described on an original document, distinguishing the positional relationships of each of the rectangular patterns on the original document and applying an optional ordering, as required, to each of the rectangular patterns.
As shown in FIG. 1, for detecting rectangular patterns drawn on an original document 100, that is, regions 101, 102 and 103 surrounded by linear lines, there has generally been employed a method of tracking the line, for instance, along a dotted arrow described counterclockwise inside of the first rectangle 101. For such tracking, the original document 100 is usually read by an image input device and the optical information on the original document 100 (such as rectangles 100-103) is converted into electrical signals and stored in an image memory such as a magnetic disc.
In this case, the data from the image input device is read into the image memory, for instance, from left to right and from the top to the bottom of the original document 100, as shown by scanning lines 104 and 105 in FIG. 1.
In the method of detecting rectangular regions by line tracking, where a magnetic disc is used as the image memory and the image data are stored by line (scanning line) in the disc, four positions each indicated with a small circular symbol have to be tracked at the n.sub.th scanning line 106 in FIG. 1. Accordingly, for the disc region where signals of the n.sub.th scanning line are stored, access has to be made 4 times, which is quite wasteful and requires a longer time for tracking and pattern recognition.